At 7:00, if you measure the resistance of the resistor using the multimeter set at Ohm measurement (the left multimeter in this case), i believe you will see that the measured resistance value is not the nominal value of the resistor. I believe its because the multimeter sees another resistance (the diode's plus the supply's) in parallel to the resistance under test. Is this a normal thing? If yes, in order to calculate the current through the voltage measurements, should i use the nominal value of the resistor at Ohm's law (I=V/R), or the aforementioned measured value? Pls let me know if what i said makes sense since english is not my native language, and elaborations might be needed. Thanks in advance, this video has been very helpful!
Hello, you should not measure the resistance using the Ohm setting on the multimeter while this circuit is connected to the power supply, this may damage the multimeter. You can measure the resistance using Ohm on the individual element when the circuit is open or power is off. The value may be a little different due to the resistance of the wire leads, it would be more accurate to use a multimeter with 4-sense Kelvin clips. Hope this helps.
@@ZGNeale It is very helpful thanks! In order to measure the current flowing through a diode, would you recommend this setup (having an ohmic resistance in series and measuring the voltage drop between its two feet) or just having the multimeter (in mA mode) in series with the diode without the use of an ohmic resistance? Should those two setups provide the same value? Thanks a lot in advance you have been of great help!
@@znsxoli you can use either method. For many data acquisition devices it is easier to measure voltage than current, so I would opt for measuring voltage across a resistor. However, if current is high then the temperature of the resistor will increase, and that will change the resistance value. You could calibrate this, there may be technical data sheets that give you the resistance at different temperatures. Another disadvantage of measuring current with the multimeter is that it must be part of the circuit, measuring voltage allows you to disconnect the multimeter whenever you want.
At 7:00, if you measure the resistance of the resistor using the multimeter set at Ohm measurement (the left multimeter in this case), i believe you will see that the measured resistance value is not the nominal value of the resistor. I believe its because the multimeter sees another resistance (the diode's plus the supply's) in parallel to the resistance under test. Is this a normal thing? If yes, in order to calculate the current through the voltage measurements, should i use the nominal value of the resistor at Ohm's law (I=V/R), or the aforementioned measured value? Pls let me know if what i said makes sense since english is not my native language, and elaborations might be needed. Thanks in advance, this video has been very helpful!
Hello, you should not measure the resistance using the Ohm setting on the multimeter while this circuit is connected to the power supply, this may damage the multimeter. You can measure the resistance using Ohm on the individual element when the circuit is open or power is off. The value may be a little different due to the resistance of the wire leads, it would be more accurate to use a multimeter with 4-sense Kelvin clips. Hope this helps.
@@ZGNeale It is very helpful thanks! In order to measure the current flowing through a diode, would you recommend this setup (having an ohmic resistance in series and measuring the voltage drop between its two feet) or just having the multimeter (in mA mode) in series with the diode without the use of an ohmic resistance? Should those two setups provide the same value? Thanks a lot in advance you have been of great help!
@@znsxoli you can use either method. For many data acquisition devices it is easier to measure voltage than current, so I would opt for measuring voltage across a resistor. However, if current is high then the temperature of the resistor will increase, and that will change the resistance value. You could calibrate this, there may be technical data sheets that give you the resistance at different temperatures. Another disadvantage of measuring current with the multimeter is that it must be part of the circuit, measuring voltage allows you to disconnect the multimeter whenever you want.
@@ZGNeale Thanks a lot for the help!